PM DC motors
PM DC motors
(OP)
Are all PM motors DC? Are all DC mtrs PM? I know its basic questions, but searching the web did not give me an answer.
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RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
Keith Cress
kcress - http://www.flaminsystems.com
RE: PM DC motors
RE: PM DC motors
Keith Cress
kcress - http://www.flaminsystems.com
RE: PM DC motors
The vast majority of AC motors are induction motors and do not have permanent magnets. Those with PM's will not have any slip, ie, the rpm at 60hz will be exactly 3600/1800/1200/or900 etc.
Servo duty motors, whether AC or DC, will not have a kw or hp listing on the nameplate and will generally say "servo" somewhere. Most but not all servo motors have permanent magnets, whether AC or DC.
RE: PM DC motors
RE: PM DC motors
Keith Cress
kcress - http://www.flaminsystems.com
RE: PM DC motors
I have sold many DC mtrs to ppl making turbines and I learn what I need as I go. I now have someone who needs a PM DC mtr to make a wind turbine.
Also, none of my Bodine gear mtrs say PM, buy they also dont have field date, so are they PM?
RE: PM DC motors
That would be almost all automotive generators from the Ford Model A up to the mid 50s and into the early 60s.Also, the original Winchargers cerca the 30s and 40s did not have permanent magnets. Self excited shunt generator that bootstrapped from residual magnetism.
http://www.wincharger.com/
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
RE: PM DC motors
That would be someone with a very narrow exposure to the electrical industry. If a conductor is moved so as to cut magnetic lines of force in a magnetic field an EMF (Voltage) will be induced in the conductor. That field may be created with either a permanent magnet or an electro-magnet. Generators above about 1/4 Hp with permanent magnet fields are a fairly recent development in the electrical industry.
Until the advent of the alternator in the mid to late 50s all automotive generators used an electromagnetic field. One of the quick tests that was sometimes performed was to power the generator on the bench. If there were no serious problems the generator would motor. This was called "Motoring the generator" With the development of high strength rare earth magnets which didn't slowly lose strength, larger PM motors and generators became feasible. In the days of steel magnets there were tachometer generators that were assembled and then magnetized. These generators could not be disassembled in the field. To do so would cause then to lose enough of their magnetic field strength that the calibration would be lost. That was about the size limit of PM machines before the development of rare earth magnets.
Bill
--------------------
"Why not the best?"
Jimmy Carter